Apparatus and method for mounting and removing tyres on and from respective wheel rims

Abstract

An apparatus for mounting and removing a tyre on and from a respective rim comprises: an element for moving a bead of the tyre in order to insert/remove the bead into/from a respective groove in the rim, the element comprising a tool connected to a respective supporting arm for moving the bead; a rotatable support for the rim, in such manner as to turn the rim and the tyre about a corresponding longitudinal axis of the rim; at least one sensor associated with the supporting arm for measuring the mechanical strain applied to the bead of the tyre when the latter is mounted on, and removed from, the rim.

What is claimed is: 
     
       1. An apparatus for mounting and removing a tyre on and from a respective rim, comprising:
 a column; 
 at least a movement element for moving a bead of the tyre, having a tool connected to a respective power-driven arm supporting the tool, wherein the movement element is supported by the column; 
 a rotatable support for supporting and moving the rim, rotatable in such manner as to turn the rim and the tyre about a corresponding longitudinal axis of the rim; 
 at least one sensor associated with the arm supporting the tool for measuring mechanical strain applied to the bead of the tyre when the tyre bead is moved by the movement element during a rotation of the rim, 
 wherein the arm includes a rod-shaped element having a first end connected to the column and a second end connected to the tool, and wherein said at least one sensor is coupled to said rod-shaped element, between the first and the second end. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the tool is a tool for inserting/removing the bead into/from a respective groove in the rim, and wherein the at least one sensor is associated with the arm for measuring the mechanical strain applied to the bead of the tyre when the latter is mounted on, and removed from, the rim. 
     
     
       3. The apparatus according to  claim 1 , wherein the tool has a hook or a lever shaped in such a way that it can be interposed between the bead and the rim in order to clutch and extract the bead. 
     
     
       4. The apparatus according to  claim 1 , wherein the tool is a bead loosening tool in the form of a rotatable disc designed to be placed on a sidewall of the tyre in such a way as to press it towards an opposite sidewall, wherein the disc is supported by said power-driven arm. 
     
     
       5. The apparatus according to  claim 1 , wherein the at least one sensor comprises a plurality of extensometers located on an outside surface of the arm. 
     
     
       6. The apparatus according to  claim 1 , wherein the arm has a cross section in the form of a polygon with an even number of sides and therefore has an even number of respective faces, pairs of extensometers being associated with respective pairs of parallel faces of the arm. 
     
     
       7. The apparatus according to  claim 6 , wherein the arm comprises a first end, directed towards the rotatable support and associated with the tool, and a second end, opposite the first end, operatively connected to a supporting column, the sensor being interposed between said first and second ends. 
     
     
       8. The apparatus according to  claim 1 , wherein said at least one sensor is a force sensor. 
     
     
       9. The apparatus according to  claim 1 , comprising an electronic control unit connected to the at least one sensor in order to receive a signal representing the mechanical strain applied to the bead and measured by the at least one sensor, the electronic control unit being programmed to process the signal and provide a user of the apparatus with an indication as to the mechanical strain the bead is subjected to. 
     
     
       10. The apparatus according to  claim 1 , comprising an electronic control unit connected at least to the sensor in order to receive a signal representing the mechanical strain applied to the bead and measured by the at least one sensor, the electronic control unit being programmed to process the signal and drive the bead movement element and/or the rim rotatable support according to the data measured by the sensor. 
     
     
       11. A method for mounting and removing a tyre on and from a respective rim, comprising the following steps:
 positioning the rim and the tyre on a rotatable support; 
 actuating a movement element supported by a column and having an arm for supporting a tool designed to interact with at least a portion of a bead of the tyre in such a way as to place said portion at a predetermined position relative to the rim, wherein the arm includes a rod-shaped element having a first end connected to the column and a second end connected to the tool; 
 turning the rim and the tyre in such a way that the movement element slides over the bead in order to insert or extract the bead itself into or from a respective groove in the rim; 
 measuring mechanical strain applied to the bead of the tyre at a zone of the bead that is operatively in contact with the movement element during tyre mounting and/or removal, using a sensor associated with 
 (i) said rod-shaped element of the arm of the movement element, between the first and the second end, and/or 
 (ii) an engagement tool engaged with a circular outside edge of the rim, through jaws that lock the rim edge there between during a rotation of the rim, in such a way that at least a portion of the tool is interposed between the edge and at least a portion of the tyre, while the rim and the tyre are turned in such a way that the movement element slides over the bead in order to insert the bead itself into the groove, wherein the engagement tool is provided with a portion for pushing the bead of the tyre towards an annular groove of the rim. 
 
     
     
       12. The method according to  claim 11 , wherein the mechanical strain applied to the tyre is measured during the entire duration of the step of turning the rim, in order to monitor the strain applied to the tyre bead as the bead is moved to the predetermined position relative to the rim. 
     
     
       13. The method according to  claim 11 , wherein measuring the mechanical strain applied to the tyre comprises the following sub-steps:
 sending a signal representing the mechanical strain to an electronic processing unit; 
 controlling the step of inserting the bead and/or the step of turning the rim in such a way that the mechanical strain does not exceed a reference value, driving means for moving a bead movement element and/or rim supporting shaft, respectively, according to said signal.